// This file is part of Moonfire NVR, a security camera network video recorder.
// Copyright (C) 2016-2020 The Moonfire NVR Authors
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// In addition, as a special exception, the copyright holders give
// permission to link the code of portions of this program with the
// OpenSSL library under certain conditions as described in each
// individual source file, and distribute linked combinations including
// the two.
//
// You must obey the GNU General Public License in all respects for all
// of the code used other than OpenSSL. If you modify file(s) with this
// exception, you may extend this exception to your version of the
// file(s), but you are not obligated to do so. If you do not wish to do
// so, delete this exception statement from your version. If you delete
// this exception statement from all source files in the program, then
// also delete it here.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/// Upgrades the database schema.
///
/// See `guide/schema.md` for more information.

use crate::db;
use failure::{Error, bail};
use log::info;
use std::ffi::CStr;
use std::io::Write;
use nix::NixPath;
use rusqlite::params;
use uuid::Uuid;

mod v0_to_v1;
mod v1_to_v2;
mod v2_to_v3;
mod v3_to_v4;
mod v4_to_v5;
mod v5_to_v6;

const UPGRADE_NOTES: &'static str =
    concat!("upgraded using moonfire-db ", env!("CARGO_PKG_VERSION"));

#[derive(Debug)]
pub struct Args<'a> {
    pub sample_file_dir: Option<&'a std::path::Path>,
    pub preset_journal: &'a str,
    pub no_vacuum: bool,
}

fn set_journal_mode(conn: &rusqlite::Connection, requested: &str) -> Result<(), Error> {
    assert!(!requested.contains(';'));  // quick check for accidental sql injection.
    let actual = conn.query_row(&format!("pragma journal_mode = {}", requested), params![],
                                |row| row.get::<_, String>(0))?;
    info!("...database now in journal_mode {} (requested {}).", actual, requested);
    Ok(())
}

fn upgrade(args: &Args, target_ver: i32, conn: &mut rusqlite::Connection) -> Result<(), Error> {
    let upgraders = [
        v0_to_v1::run,
        v1_to_v2::run,
        v2_to_v3::run,
        v3_to_v4::run,
        v4_to_v5::run,
        v5_to_v6::run,
    ];

    {
        assert_eq!(upgraders.len(), db::EXPECTED_VERSION as usize);
        let old_ver =
            conn.query_row("select max(id) from version", params![],
                           |row| row.get(0))?;
        if old_ver > db::EXPECTED_VERSION {
            bail!("Database is at version {}, later than expected {}",
                  old_ver, db::EXPECTED_VERSION);
        } else if old_ver < 0 {
            bail!("Database is at negative version {}!", old_ver);
        }
        info!("Upgrading database from version {} to version {}...", old_ver, target_ver);
        set_journal_mode(&conn, args.preset_journal)?;
        for ver in old_ver .. target_ver {
            info!("...from version {} to version {}", ver, ver + 1);
            let tx = conn.transaction()?;
            upgraders[ver as usize](&args, &tx)?;
            tx.execute(r#"
                insert into version (id, unix_time, notes)
                             values (?, cast(strftime('%s', 'now') as int32), ?)
            "#, params![ver + 1, UPGRADE_NOTES])?;
            tx.commit()?;
        }
    }

    Ok(())
}

pub fn run(args: &Args, conn: &mut rusqlite::Connection) -> Result<(), Error> {
    db::set_integrity_pragmas(conn)?;
    upgrade(args, db::EXPECTED_VERSION, conn)?;

    // WAL is the preferred journal mode for normal operation; it reduces the number of syncs
    // without compromising safety.
    set_journal_mode(&conn, "wal")?;
    if !args.no_vacuum {
        info!("...vacuuming database after upgrade.");
        conn.execute_batch(r#"
            pragma page_size = 16384;
            vacuum;
        "#)?;
    }
    info!("...done.");

    Ok(())
}

/// A uuid-based path, as used in version 0 and version 1 schemas.
struct UuidPath([u8; 37]);

impl UuidPath {
    pub(crate) fn from(uuid: Uuid) -> Self {
        let mut buf = [0u8; 37];
        write!(&mut buf[..36], "{}", uuid.to_hyphenated_ref())
            .expect("can't format uuid to pathname buf");
        UuidPath(buf)
    }
}

impl NixPath for UuidPath {
    fn is_empty(&self) -> bool { false }
    fn len(&self) -> usize { 36 }

    fn with_nix_path<T, F>(&self, f: F) -> Result<T, nix::Error>
    where F: FnOnce(&CStr) -> T {
        let p = CStr::from_bytes_with_nul(&self.0[..]).expect("no interior nuls");
        Ok(f(p))
    }
}

#[cfg(test)]
mod tests {
    use crate::compare;
    use crate::testutil;
    use failure::ResultExt;
    use fnv::FnvHashMap;
    use super::*;

    const BAD_ANAMORPHIC_VIDEO_SAMPLE_ENTRY: &[u8] =
        b"\x00\x00\x00\x84\x61\x76\x63\x31\x00\x00\
          \x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\
          \x00\x00\x00\x00\x00\x00\x01\x40\x00\xf0\x00\x48\x00\x00\x00\x48\
          \x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\
          \x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\
          \x00\x00\x00\x00\x00\x00\x00\x00\x00\x18\xff\xff\x00\x00\x00\x2e\
          \x61\x76\x63\x43\x01\x4d\x40\x1e\xff\xe1\x00\x17\x67\x4d\x40\x1e\
          \x9a\x66\x0a\x0f\xff\x35\x01\x01\x01\x40\x00\x00\xfa\x00\x00\x03\
          \x01\xf4\x01\x01\x00\x04\x68\xee\x3c\x80";

    const GOOD_ANAMORPHIC_VIDEO_SAMPLE_ENTRY: &[u8] =
        b"\x00\x00\x00\x9f\x61\x76\x63\x31\x00\x00\x00\x00\x00\x00\x00\x01\
          \x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\
          \x02\xc0\x01\xe0\x00\x48\x00\x00\x00\x48\x00\x00\x00\x00\x00\x00\
          \x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\
          \x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\
          \x00\x00\x00\x18\xff\xff\x00\x00\x00\x49\x61\x76\x63\x43\x01\x64\
          \x00\x16\xff\xe1\x00\x31\x67\x64\x00\x16\xac\x1b\x1a\x80\xb0\x3d\
          \xff\xff\x00\x28\x00\x21\x6e\x0c\x0c\x0c\x80\x00\x01\xf4\x00\x00\
          \x27\x10\x74\x30\x07\xd0\x00\x07\xa1\x25\xde\x5c\x68\x60\x0f\xa0\
          \x00\x0f\x42\x4b\xbc\xb8\x50\x01\x00\x05\x68\xee\x38\x30\x00";

    fn new_conn() -> Result<rusqlite::Connection, Error> {
        let conn = rusqlite::Connection::open_in_memory()?;
        conn.execute("pragma foreign_keys = on", params![])?;
        conn.execute("pragma fullfsync = on", params![])?;
        conn.execute("pragma synchronous = 2", params![])?;
        Ok(conn)
    }

    fn compare(c: &rusqlite::Connection, ver: i32, fresh_sql: &str) -> Result<(), Error> {
        let fresh = new_conn()?;
        fresh.execute_batch(fresh_sql)?;
        if let Some(diffs) = compare::get_diffs("upgraded", &c, "fresh", &fresh)? {
            panic!("Version {}: differences found:\n{}", ver, diffs);
        }
        Ok(())
    }

    /// Upgrades and compares schemas.
    /// Doesn't (yet) compare any actual data.
    #[test]
    fn upgrade_and_compare() -> Result<(), Error> {
        testutil::init();
        let tmpdir = tempdir::TempDir::new("moonfire-nvr-test")?;
        //let path = tmpdir.path().to_str().ok_or_else(|| format_err!("invalid UTF-8"))?.to_owned();
        let mut upgraded = new_conn()?;
        upgraded.execute_batch(include_str!("v0.sql"))?;
        upgraded.execute_batch(r#"
            insert into camera (id, uuid, short_name, description, host, username, password,
                                main_rtsp_path, sub_rtsp_path, retain_bytes)
                        values (1, zeroblob(16), 'test camera', 'desc', 'host', 'user', 'pass',
                                'main', 'sub', 42);
        "#)?;
        upgraded.execute(r#"
            insert into video_sample_entry (id, sha1, width, height, data)
                values (1, X'0000000000000000000000000000000000000000', 1920, 1080, ?);
        "#, params![testutil::TEST_VIDEO_SAMPLE_ENTRY_DATA])?;
        upgraded.execute(r#"
            insert into video_sample_entry (id, sha1, width, height, data)
                values (2, X'0000000000000000000000000000000000000001', 320, 240, ?);
        "#, params![BAD_ANAMORPHIC_VIDEO_SAMPLE_ENTRY])?;
        upgraded.execute(r#"
            insert into video_sample_entry (id, sha1, width, height, data)
                values (3, X'0000000000000000000000000000000000000002', 704, 480, ?);
        "#, params![GOOD_ANAMORPHIC_VIDEO_SAMPLE_ENTRY])?;
        upgraded.execute(r#"
            insert into video_sample_entry (id, sha1, width, height, data)
                values (4, X'0000000000000000000000000000000000000003', 704, 480, ?);
        "#, params![GOOD_ANAMORPHIC_VIDEO_SAMPLE_ENTRY])?;
        upgraded.execute_batch(r#"
            insert into recording (id, camera_id, sample_file_bytes, start_time_90k, duration_90k,
                                   local_time_delta_90k, video_samples, video_sync_samples,
                                   video_sample_entry_id, sample_file_uuid, sample_file_sha1,
                                   video_index)
                           values (1, 1, 42, 140063580000000, 90000, 0, 1, 1, 1,
                                   X'E69D45E8CBA64DC1BA2ECB1585983A10', zeroblob(20), X'00'),
                                  (2, 1, 42, 140063580090000, 90000, 0, 1, 1, 2,
                                   X'94DE8484FF874A5295D488C8038A0312', zeroblob(20), X'00'),
                                  (3, 1, 42, 140063580180000, 90000, 0, 1, 1, 3,
                                   X'C94D4D0B533746059CD40B29039E641E', zeroblob(20), X'00');
            insert into reserved_sample_files values (X'51EF700C933E4197AAE4EE8161E94221', 0),
                                                     (X'E69D45E8CBA64DC1BA2ECB1585983A10', 1);
        "#)?;
        let rec1 = tmpdir.path().join("e69d45e8-cba6-4dc1-ba2e-cb1585983a10");
        let rec2 = tmpdir.path().join("94de8484-ff87-4a52-95d4-88c8038a0312");
        let rec3 = tmpdir.path().join("c94d4d0b-5337-4605-9cd4-0b29039e641e");
        let garbage = tmpdir.path().join("51ef700c-933e-4197-aae4-ee8161e94221");
        std::fs::File::create(&rec1)?;
        std::fs::File::create(&rec2)?;
        std::fs::File::create(&rec3)?;
        std::fs::File::create(&garbage)?;

        for (ver, fresh_sql) in &[(1, Some(include_str!("v1.sql"))),
                                  (2, None),  // transitional; don't compare schemas.
                                  (3, Some(include_str!("v3.sql"))),
                                  (4, None),  // transitional; don't compare schemas.
                                  (5, Some(include_str!("v5.sql"))),
                                  (6, Some(include_str!("../schema.sql")))] {
            upgrade(&Args {
                sample_file_dir: Some(&tmpdir.path()),
                preset_journal: "delete",
                no_vacuum: false,
            }, *ver, &mut upgraded).context(format!("upgrading to version {}", ver))?;
            if let Some(f) = fresh_sql {
                compare(&upgraded, *ver, f)?;
            }
            if *ver == 3 {
                // Check that the garbage files is cleaned up properly, but also add it back
                // to simulate a bug prior to 433be217. The v5 upgrade should take care of
                // anything left over.
                assert!(!garbage.exists());
                std::fs::File::create(&garbage)?;
            }
            if *ver == 6 {
                // Check that the pasp was set properly.
                let mut stmt = upgraded.prepare(r#"
                    select
                      id,
                      pasp_h_spacing,
                      pasp_v_spacing
                    from
                      video_sample_entry
                "#)?;
                let mut rows = stmt.query(params![])?;
                let mut pasp_by_id = FnvHashMap::default();
                while let Some(row) = rows.next()? {
                    let id: i32 = row.get(0)?;
                    let pasp_h_spacing: i32 = row.get(1)?;
                    let pasp_v_spacing: i32 = row.get(2)?;
                    pasp_by_id.insert(id, (pasp_h_spacing, pasp_v_spacing));
                }
                assert_eq!(pasp_by_id.get(&1), Some(&(1, 1)));
                assert_eq!(pasp_by_id.get(&2), Some(&(4, 3)));
                assert_eq!(pasp_by_id.get(&3), Some(&(40, 33)));

                // No recording references this video_sample_entry, so it gets dropped on upgrade.
                assert_eq!(pasp_by_id.get(&4), None);
            }
        }

        // Check that recording files get renamed.
        assert!(!rec1.exists());
        assert!(tmpdir.path().join("0000000100000001").exists());

        // Check that garbage files get cleaned up.
        assert!(!garbage.exists());

        Ok(())
    }
}
